The effects of polycentric evolution on commute times in a polycentric compact city: A case of the Seoul Metropolitan Area

This study attempts to investigate the dynamics of polycentric evolution and the changing roles of existing and new employment centers in determining commuting patterns. For this purpose, we analyze temporal changes in urban form and individual commuting behavior between 2000 and 2015 for the Seoul Metropolitan Area (SMA)-an area that has experienced rapid employment growth and changes in urban form over the last half-century. Results reveal both positive and negative effects on commuting efficiency. On the positive side, inner-city subcenter commuters have significantly reduced commute times over the last 15 years, possibly due to locational adjustment (i.e., the reduction of commute distance), improvement in public transit accessibility, and the emergence of new suburban subcenters that attract workers who previously traveled to inner-city subcenters. On the negative side, these new suburban subcenters have also attracted more workers from a wider job market, resulting in longer commute times for suburban subcenter commuters. The evidence suggests that mixed land use for development and improvements in public transit accessibility are important drivers of commuting efficiency, while improving public transport directly leads to shorter commute times in high-density urban areas.